The goal of this project is to establish the mechanism(s) by which arachidonate is released from human neutrophils during phagocytosis and the nature of the prostaglandin(s) and hydroxylated derivatives that are formed from the released arachidonate. In order to achieve these goals, we will identify the phospholipid(s) that is the precursor of the released arachidonate and the pathways by which the arachidonate is incorporated into and released from the membrane lipid. Special emphasis will be placed on the deacylation-reacylation pathway of phospholipid turnover. It is reasonable to assume that the events in arachidonate metabolism occur on the plasma membrane since the metabolites are released into the medium. This hypothesis, however, will be rigorously tested by the isolation of the cellular plasma membranes and other organelles. The products of arachidonate metabolism will be isolated and characterized by thin-layer, high pressure- and gas-liquid chromatography; high pressure liquid chromatography will be used to isolate the metabolites to test for their capacity to regulate the physiologic function of neutrophils. The functions to be studied are aggregation, chemotaxis, hexose transport, degranulation, hexose shunt, superoxide generation, protein iodination and chemiluminescence. The results of these studies will more clearly define the role of arachidonate metabolism in host defense and inflammatory reactions.